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Switchable power transformer or not? MUsic HAll conundrum

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Posted on August 30, 2015 at 03:23:12
MEDiASAPiENS
Audiophile

Posts: 2
Joined: August 30, 2015

Hello mates. I need an advice of someone with more technical knowledge. I brought my favorite receiver from US to EU, 110V to 220V.
Before I moved I contacted Roy at Music Hall Audio and asked if they can swap power supply in my receiver for 220V model? First he sounded promising but when I decided to drive over and drop my receiver off he changed his mind and said they don't really do such mods.I was disappointed , because I knew they have voltage switchable amps in their lineup , so it was not an issue of not having correct replacement transformer.
I have used my Maven with a step down transformer (1500W) and neither of them are running hot. However recently I've opened the top of Maven for cleaning and what do I see, well you tell me. Do I see a universal voltage transformer that could be switched to 220? And if that is the case , how do I switch that sucker?

MEDiASAPiENS

 

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RE: Switchable power transformer or not? MUsic HAll conundrum, posted on August 30, 2015 at 05:51:28
Victor Khomenko
Manufacturer

Posts: 55319
Joined: April 5, 2000
 According to that diagram it is indeed switchable, but how - can't tell you, you need to look for the place where the primary leads terminate, likely there is a barrier block or some kind of jumper arrangement that should be changed. Follow the leads.


 

RE: Switchable power transformer or not? MUsic HAll conundrum, posted on August 30, 2015 at 08:30:18
Awe-d-o-file
Dealer

Posts: 21037
Location: 50 miles west of DC
Joined: January 10, 2004
 I agree w/Victor that indeed it is a dual voltage primary transformer. You or someone will have to take it apart. It seems to unscrew from the bottom. The two wires connected to the primary side need to be changed to the ones that accept 220. Good luck.


You really have to give Roy/Music Hall a thumbs down for this. If he did say " they (we) don't really do such mods" that's crap. Who is more qualified to do such a fairly easy thing than the manufacturer? Also it really isn't a modification its an option change.


E
T

ET

"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936

 

Which begs the question, posted on August 30, 2015 at 08:44:01
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 If it is that easy, then why didn't Hall make the switch, and earn some fast money? Don't get me wrong, I'm with you, Mr. K. After looking at the diagram on the top of the transformer, it should be exactly that easy. The only thing the transformer doesn't tell you is what color lead you would use to convert it to 220V.

MEDiASAPiENS, have you taken the bottom plate off, to see if there's any markings on the underside of the transformer? Mr. Khomenko's right, that's your next step.

Good luck with it.


 

There are TWO good reasons why there is no switch, posted on August 30, 2015 at 10:01:15
Victor Khomenko
Manufacturer

Posts: 55319
Joined: April 5, 2000
 First one - there are FIVE possible voltages, so it would have to be one complicated switch.

And second one - a permanent connection, with spade lugs under screw terminals, will always be much more reliable, than any switch.


 

A misinterpretation of the word "switch", posted on August 30, 2015 at 11:33:18
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 I didn't mean a physical toggle switch. What I meant was that I wondered why Hall didn't make the change, meaning why didn't he unsolder the 120V lead, and connect the 220V lead. Switch places, in other words.

 

The answer..., posted on August 30, 2015 at 11:38:47
Victor Khomenko
Manufacturer

Posts: 55319
Joined: April 5, 2000
 ...most likely lies with their policies. I can't speak for that aspect.


 

RE: The answer..., posted on August 30, 2015 at 12:08:16
Awe-d-o-file
Dealer

Posts: 21037
Location: 50 miles west of DC
Joined: January 10, 2004
 It does seem somewhere between odd and silly they didn't do the work considering the part MH chose to use.


E
T

ET

"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936

 

RE: Switchable power transformer or not? MUsic HAll conundrum, posted on August 30, 2015 at 13:31:35
Caucasian Blackplate
Industry Professional

Posts: 8313
Location: Seattle
Joined: June 18, 2004
 It's too bad that sticker isn't just a hair more informative.

A decent tech with a meter and some patience could change that amp around for 220V operation.

There's also the slight possibility that the transformer under that cover isn't consistent with the diagram on the sticker.

 

RE: " I can't speak for that aspect.", posted on August 30, 2015 at 15:13:50
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 I wasn't expecting you to speak to it, of course. I know there's no way you could. I was simply pondering why a company might build a receiver using a more expensive multi-tapped power transformer, and then not do a simple conversion on something which was hand delivered to them.

I suppose we'll never know.

 

Does the unit have an IEC power inlet with, posted on August 30, 2015 at 16:34:23
G Squared
Audiophile

Posts: 8487
Location: Washington, DC Metro Area
Joined: November 16, 2004
Contributor
  Since: May 23, 2023
 A detachable cord set or a permanently attached power cord?
Gsquared

 

If you can take off the PT cover..., posted on August 30, 2015 at 23:49:55
Frihed89
Audiophile

Posts: 15703
Location: Copenhagen
Joined: March 21, 2005
 You probably will find the mfr's name and model. If so, check the internet to see if there is enough to rewire it to 240. If not, look them up and call them. EU voltage is 230VAC/50. UK is 240VAC/50. The latter will work fine in the EU.

 

Yep, posted on August 31, 2015 at 05:52:10
Awe-d-o-file
Dealer

Posts: 21037
Location: 50 miles west of DC
Joined: January 10, 2004
 total BS really. No excuse. An easy change.


E
T

ET

"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936

 

RE: Switchable power transformer or not? MUsic HAll conundrum, posted on August 31, 2015 at 06:56:42
wheezer
Audiophile

Posts: 4309
Joined: January 24, 2001
 Call Music Hall again and ask for Leland.
He'll guide you to the proper primary tap color for your needs.

Cheers,
W

 

RE: Switchable power transformer or not? MUsic HAll conundrum, posted on August 31, 2015 at 11:59:18
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 MY question would be that IF you are in a 230v country and it really IS hovering at 230+-2 or 3 vac, than which tap WOULD you use? 220 or 240?

Is there is do not exceed rule or would you perhaps cause excess output voltage?

Here At my house, my voltage in is about 117 or 118 MOST of the time, falling to in the 116 range during 'peak' demand times in summer. I would be inclined to go to the 120 tap, but what WOULD happen if I were to use the 110 tap?

It wouldn't surprise me if the input Color Code were on the UNDERSIDE of the removable transformer shell. or otherwise attached.
Too much is never enough

 

RE: Switchable power transformer or not? MUsic HAll conundrum, posted on August 31, 2015 at 12:47:24
Victor Khomenko
Manufacturer

Posts: 55319
Joined: April 5, 2000
 ***MY question would be that IF you are in a 230v country and it really IS hovering at 230+-2 or 3 vac, than which tap WOULD you use? 220 or 240?***

One can not answer this question intelligently without knowing the design details of that product. Some units may indeed have components overstressed when using 220V setting, but they might produce a bit more power. It is generally safer to configure it for 240V.

Remember also, that 220, 230 or 240V operation usually also means 50Hz, which is MUCH harder on the transformer.


 

RE: Switchable power transformer or not? MUsic HAll conundrum, posted on August 31, 2015 at 20:25:42
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 What I understand about transformers is that a 50hz unit will work fine @60hz while a 60 may or may not work properly @50. I think I remember correctly.
Please correct me if I'm wrong.


I would also suspect that as downstream power supplies MAY be regulated, the slight over voltage won't make any difference. In a SS amp, for example, if the PS kicks out 50vdc, you may use some over rated filter cap. Certainly, IMO, no LESS than 60v

On the original picture of the transformer, I see 6.8v which implies HEATER, right? I doubt that is regulated so I don't know how much over it can stand?
Too much is never enough

 

RE: Switchable power transformer or not? MUsic HAll conundrum, posted on September 1, 2015 at 04:57:06
Victor Khomenko
Manufacturer

Posts: 55319
Joined: April 5, 2000
 You are correct on the transformer - basically, the 50Hz model must have more iron in its core.

The rest is just a conjecture, we do not know the internal details.

In case of that 6.8V several things could be happening. For instance, it could be fed to the filaments through resistors, dropping a fraction of a volt - good practice, softening the inrush current. Or it could be rectified and then regulated, maybe down to 5V.

I don't like making wild guesses, I presume the designers knew what they were doing... unless shown otherwise. :)


 

RE: Switchable power transformer or not? MUsic HAll conundrum, posted on September 2, 2015 at 10:27:24
Tom Schuman
Audiophile

Posts: 2632
Location: Bremen
Joined: October 22, 2003
 Everything is built in China, I'd be surprised if they even knew how to do it. AFAIK Hall is a marketing guy, not a technician.......

 

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